Accessibility in key areas of the Arctic in the 21st mid-century

The navigation potential of the Arctic has improved with the rapid retreat of sea ice under continuous warming.The comprehensive evaluation of Arctic accessibility for low ice-breaking ships(civil use)in the mid-century is important to support coordinated international decision-making.In this study,the hydrological conditions and navigation potential in key areas and crucial straits along the Northern Sea Route(NSR)and Northwest Passage(NWP)were assessed under Shared Socioeconomic Pathways(SSPs)using the Polar Operational Limit Assessment Risk Indexing System.The results showed that the most critical areas for navigation in the mid-century(2046-2055)are the waters around the New Siberian Islands and within the Parry Channel.Arctic navigability improves from SSP1-2.6 to SSP2-4.5 to SSP5-8.5,and the accessibility for PC7 ships under SSP2-4.5 is even better for OW ships under SSP5-8.5.The route on the north side of the New Siberian Islands is a relatively good choice within the NSR,and the southern route has a better navigation potential than the Parry Channel within the NWP.In addition,the accessibility of the Dmitri Laptev Strait is better than that of the Sannikov Strait at a monthly scale,although the latter has more navigable days.However,there is little difference in accessibility between the eastern and western parts of the Parry Channel.The best nav-igation potential through the above straits is in September for ordinary ships,and the optimal time window is delayed and extended for PC7 ships.The results can serve as references for policy-making and navigation planning in the Arctic.

Impacts of 1.5℃ global warming on hydrological conditions of navigation along the Northern Sea Route and Northwest Passage

Arctic navigability is crucial to the global economy and landscape,while there is an omission in understanding how Arctic navigability changes as a function of 1.5℃ of the Paris Agreement.This study investigated the impact of 1.5℃ global warming above the preindustrial level on sea ice conditions and accessibility of the Northern Sea Route(NSR)and Northwest Passage(NWP)with the Polar Operational Limit Assessment Risk Indexing System and new risk demarcation criteria.The Arctic is colder on the Canadian side than on the European side under 1.5℃ warming.Sea ice is mostly less than three years old,and the younger,thinner and less concentrated ice is mainly in the seas along the NSR.Ships above Polar Class(PC)6 might be unimpeded along two passages all the year.Besides,the NSR and NWP have great potential for PC6 ships in October-December,while it is only the NSR for PC7 ships.Caution is still required when navigating the western East Siberian Sea,its surrounding straits,and the Parry Channel.These changes in hydrological conditions are important for global shipping,and this work is helpful for supporting coordinated international decision-making.